Unreal Engine Issues
Unreal Engine Issues
Alpha blending is done twice when using RenderOpacity of RetainerBox's parent slot
UE - Editor - UI Systems - UMG - Feb 10, 2023Licensee reported that alpha blending is done twice in the code below, and the fix below seems to fix it. .\Engine\Source\Runtime\UMG\Private\Slate\SRetainerWidget.cpp From:const FLinearColor Compu ...
[Soundfield Submix][Crash] - Unreal Ambisonics Crashes on Packaged Game and in Standalone
UE - Audio - Submixes - Jan 11, 2021Issue was reported by a user on the Unreal Engine forms. I tried to package the game with the other encoding options and this appears specific to using the Unreal Ambisonics option. I have only co ...
GPU-ARM Mali 400 series phones will render an Opaque Unlit Material as black
UE - Platform - Mobile - Feb 12, 2016ARM Mali 400 Series GPUs are rendering Opaque Unlit Materials as Black instead of the designated color. This is a *regression* from 4.10.2.Devices where Issue OccursDevice NameBrandBug Description ...
Crash in GameplayTag Editor Widget when editing array of tags on a component
UE - Gameplay - May 17, 2022Editing an array of gameplay tags on a component belonging to an actor instance can lead to a crash. There are inconsistencies with how the Gameplay Tag Editor widget behaves:Array of gameplay tags ...
Crash: Changing Material Property Overrides of Material Instance
UE - Graphics Features - Dec 14, 2016When a material has a static bool parameter AND this is overridden in a material instance, Trying to change Blend Mode or Shading Model under the Material Property Overrides crashes the editor. Thi ...
VC Runtime not in UnrealLightmass temp directory; causing lightmass build errors
UE - Foundation - Cpp Tools - UnrealBuildTool - Oct 14, 2015A Redistribute file for VS 2015 is needed to build lightmass, but this is not currently included with the engine. If a user does not have VS 2015 installed, lightmass will fail with this error: Un ...
Collision Drawing in Cooked Builds (Development) doesn't Show Geometry for Nanite Meshes
UE - Graphics Features - Jun 2, 2025Context The showFlag.CollisionVisibility 1 cvar is a viewport visualization mode that highlights which Actors will block visibility. The showFlag.CollisionPawn 1 cvar is a Player Collision viewmode ...
Disabled Skeletal Mesh Sections cause Shadow Ray Tracing Flicker
UE - Rendering - Graphics Features - Ray Tracing - Dec 12, 2025If a skeletal mesh has a section disabled the ray traced shadow will flicker when the camera or itself moves. Previously in 5.6.0 no raytraced shadow would appear if a section was disabled. This wa ...
Regression: FAnimInstanceProxy memory leak when BeginDestroy() called on UAnimInstance before USkeletalMeshComponent
UE - Anim - Runtime - Feb 10, 2025In UE 5.5, the fix applied by CL 36529858 in ue5-main updated USkeletalMeshComponent::ClearAnimScriptInstance() to call AnimScriptInstance::UninitializeAnimation() on the animation instance. This, i ...
Mutable constant texture variable with ClipUV mask only works with new experimental dynamic variable is connected as well
UE - Anim - Mutable - Sep 22, 2025We are attempting to use Mutable in 5.6.1 and have encountered an issue which we are not sure how to resolve. The issue occurs when using the ClipWithUVMask node. In short we have a customizable o ...